Stored Procedure looping

I am looking for the ways to reduce the looping for the below stored procedure. This takes around 30 minutes to loop around 30,000 records. Let me know if there are ways to rewrite the stored procedure.

  DECLARE
      @startloop numeric(9, 0),
      @endloop numeric(9, 0),
      @posloop numeric(9, 0),
      @memid numeric(9, 0),
      @groupid numeric(9, 0),
      @billfreq char(1),
      @recid numeric(10, 0),
      @currptd datetime,
      @joindate datetime,
      @recdate datetime,
      @a_dt_rundate datetime,
      @recamt money,
      @l_m_arrears money,
      @l_m_advance money,
      @l_m_arrears_no_other money,
      @l_m_advance_no_other money,
      @l_m_arrsub money,
      @l_m_advsub money,
      @l_m_arrreb money,
      @l_m_advreb money,
      @l_m_memcont money,
      @l_m_arrlhc money,
      @l_m_advlhc money,
      @l_m_arroth money,
      @l_m_advoth money,
      @l_m_arrbreakup numeric(9, 0),
      @l_m_advbreakup numeric(9, 0),
      @l_m_arrpercent numeric(12, 8),
      @l_m_advpercent numeric(12, 8),
      @percentage numeric(12, 8),
      @l_m_unarrears  money,
      @l_m_unarreb  money,
      @l_m_unarsub  money,
      @l_m_unarlhc  money,
      @l_m_unaroth  money,
      @l_m_unarbreakup  money,
      @l_m_cover_total money ,
      @recamt_threshold money,
      @rebate_tier_id int
     
   SELECT
      @recdate = NULL,
      @currptd = NULL,
      @recamt = NULL,
      @l_m_advance = 0,
      @l_m_arrears = 0,
      @recid = NULL,
      @l_m_memcont = 0,
      @groupid = NULL,
      @billfreq = NULL,
      @l_m_arrsub = NULL,
      @l_m_advsub = NULL,
      @l_m_arrreb = NULL,
      @l_m_advbreakup = NULL,
      @l_m_arrbreakup = NULL,
      @l_m_advreb = NULL,
      @l_m_arrears_no_other = 0,
      @l_m_advance_no_other = 0,
      @l_m_unarrears = 0 ,
      @l_m_unarreb = NULL,
      @l_m_unarsub = NULL,
      @l_m_unarlhc = NULL,
      @l_m_unaroth = NULL,
      @l_m_unarbreakup = NULL,
      @recamt_threshold = 0,
      @rebate_tier_id = null

   SELECT @startloop = min(row_id), @endloop = max(row_id), @a_dt_rundate = dateadd(dd,  -1, @l_dt_run)
   FROM #members_arr
  
   SELECT @posloop = @startloop
  
   WHILE @posloop <= @endloop
  
      BEGIN
         /* Get member_id*/
         SELECT @memid = #members_arr.membership_id, @currptd = date_paidto, @joindate = join_date, @groupid = group_id, @recid = rec_id
         FROM #members_arr
         WHERE row_id = @posloop
        
         SELECT @recdate = dbo.rept.new_paid_to,
         @recamt = dbo.rept.receipt_amount
         FROM dbo.rept
         WHERE dbo.rept.membership_id = @memid AND dbo.rept.rept_id = @recid
        
         SELECT TOP 1 @rebate_tier_id = rebate_memship_tier.rebate_tier_id
         FROM rebate_memship_tier
         WHERE membership_id = @memid
         ORDER BY effective_date DESC
        
         -- Disable Receipt Proportionality Functionality
      SELECT  @recamt = null

         IF (@recdate IS NULL OR @recdate < @joindate)
            BEGIN
               SELECT @recdate = @currptd
               -- PRINT 'NULL'
            END

   IF @recdate < dateadd(dd,  -1, @l_dt_run)
            BEGIN

               EXECUTE dbo.p_cal_rept_approx_ptd
                  @memid,
                  @recdate,
                  @a_dt_rundate,
                  'N',
                  @l_m_arrears  OUTPUT,
                  @l_m_arrreb  OUTPUT,
                  @l_m_arrsub  OUTPUT,
                  @l_m_arrlhc  OUTPUT,
                  @l_m_arroth  OUTPUT,
                  @l_m_arrbreakup  OUTPUT,
                  @percentage  OUTPUT,
                  @rebate_tier_id

               SELECT @l_m_arrears = @l_m_arrears + @l_m_arrreb + @l_m_arrsub
               SELECT @l_m_arrears_no_other = @l_m_arrears - @l_m_arroth
            END

           
  SELECT @billfreq = dbo.billing_group.billing_freq
  FROM dbo.billing_group
  WHERE dbo.billing_group.group_id = @groupid
  
   PRINT 'rebate tier id' + isnull(cast(@rebate_tier_id as varchar(max)),'[null]')
  
  /* Get member's standard contribution*/
  EXECUTE dbo.p_calc_nettfee_lhc
   @memid,
   NULL,
   @l_dt_run,
   @billfreq,
   1,
   @percentage,
   NULL,
   NULL,
   NULL,
   NULL,
   NULL,
   NULL,
   NULL,
   @l_m_cover_total OUTPUT,
   NULL,
   NULL,
   @l_m_memcont  OUTPUT,
   NULL,
   NULL,
   NULL,
   @rebate_tier_id
    
             IF @l_m_arrears > 0
   BEGIN
    -- PRINT 'Record: ' + CAST(@posloop AS varchar(max)) + '  Member: ' + CAST(@memid AS varchar(max)) + '   Date Paid: ' + CAST(@recdate AS varchar(max)) + ' Cont: ' + CAST(@l_m_memcont AS varchar(max))+ ' '
    SELECT @l_m_unarrears = 0.0
    EXEC p_calc_arrears_unearned  @recdate, @l_dt_run, @billfreq, @l_m_cover_total, @l_m_unarrears OUTPUT       
            END  
  ELSE                
   SELECT @l_m_unarrears = 0.0
              
   
         /* Update #members_arr table with key data*/
         UPDATE #members_arr
            SET
               date_paidto = @recdate,
               member_arrears = @l_m_arrears,
               member_advance = @l_m_advance,
               member_arrears_no_other = @l_m_arrears_no_other,
               member_advance_no_other = @l_m_advance_no_other,
               member_cont = isnull(@l_m_memcont, 0),
               member_arrears_unearned=@l_m_unarrears
         WHERE row_id = @posloop

         /* reset loop variables*/
         SELECT
            @recdate = NULL,
            @recamt = NULL,
            @currptd = NULL,
            @l_m_advance = 0,
            @l_m_arrears = 0,
            @recid = NULL,
            @l_m_memcont = 0,
            @groupid = NULL,
            @billfreq = NULL,
            @l_m_arrsub = NULL,
            @l_m_advsub = NULL,
            @l_m_arrreb = NULL,
            @l_m_advbreakup = NULL,
            @l_m_arrbreakup = NULL,
            @l_m_advreb = NULL,
            @l_m_arrears_no_other = 0,
            @l_m_advance_no_other = 0,
            @rebate_tier_id = null

         /* Increment counter*/
         SELECT @posloop = @posloop + 1